TMOD-33. DOES PRE-CLINICAL DRUG ACTIVITY PREDICT PHASE II CLINICAL EFFICACY IN GLIOBLASTOMA? A DETAILED ANALYSIS

Abstract Despite decades of research, there are fewer than six FDA-approved therapies for glioblastoma (GBM). The drug approval process relies on studies establishing pre-clinical activity, most commonly using murine models, followed by in human studies establishing safety and then efficacy. Although murine models for GBM have allowed for insights into tumor biology, their utility in assessing the efficacy of novel anti-cancer therapies remains highly debated. Here, we sought to establish whether there was any relationship between drug activity in preclinical models and phase 2 clinical trial outcomes. Using ClinicalTrials.gov (NIH), all phase 2 trials in glioblastoma up to December 2023 were queried and downloaded. Trials that were never started, had not yet started, were withdrawn, not completed, or contained indications beyond glioblastoma were excluded. Studies examining anti-tumor effects of an investigational agent with or without bevacizumab, temozolomide, or radiation therapy in glioblastoma were included, and studies examining alternative dosing strategies, various medical devices, or drug combinations, were excluded. The corresponding preclinical studies were identified via literature review for each clinical trial. Data including the progression free and overall survival benefit, mouse models used, and sample sizes were extracted from each study. 659 trials between 1994 and 2023 were included for analysis. Of these, 272 (41%) were for monotherapies, examining 90 unique small molecules. Preclinical endpoints included murine survival and tumor weight. In comparing mouse survival and tumor size to progression free and overall survival in humans, our preliminary analysis did not reveal any clear correlation. The correlation between preclinical and clinical drug response in GBM remains uncertain. Future work will examine whether mouse genotype, immune status, or GBM cell line used affected the degree of concordance with human clinical trial data. Our analysis suggests that further investigation into preclinical models of GBM, and standardized reporting of preclinical models, are needed.